<!DOCTYPE html>
<html lang="en">
	<head>
		<title>three.js webgl - interactive particles</title>
		<meta charset="utf-8">
		<meta name="viewport" content="width=device-width, user-scalable=no, minimum-scale=1.0, maximum-scale=1.0">
		<style>
			body {
				color: #ffffff;
				background-color: #000000;
				margin: 0px;
				overflow: hidden;
			}
			#info {
				position: absolute;
				top: 0px;
				width: 100%;
				padding: 5px;
				font-family: Monospace;
				font-size: 13px;
				text-align: center;
				font-weight: bold;
			}
			a {
				color: #fff;
			}
		</style>
	</head>

	<body>
		<div id="container"></div>
		<div id="info"><a href="http://threejs.org" target="_blank">three.js</a> webgl - interactive - particles</div>

		<script src="../build/three.js"></script>

		<script src="js/Detector.js"></script>
		<script src="js/libs/stats.min.js"></script>

		<script type="x-shader/x-vertex" id="vertexshader">

			attribute float size;
			attribute vec3 customColor;

			varying vec3 vColor;

			void main() {

				vColor = customColor;

				vec4 mvPosition = modelViewMatrix * vec4( position, 1.0 );

				gl_PointSize = size * ( 300.0 / -mvPosition.z );

				gl_Position = projectionMatrix * mvPosition;

			}

		</script>

		<script type="x-shader/x-fragment" id="fragmentshader">

			uniform vec3 color;
			uniform sampler2D texture;

			varying vec3 vColor;

			void main() {

				gl_FragColor = vec4( color * vColor, 1.0 );

				gl_FragColor = gl_FragColor * texture2D( texture, gl_PointCoord );

				if ( gl_FragColor.a < ALPHATEST ) discard;

			}

		</script>


		<script>

			if ( ! Detector.webgl ) Detector.addGetWebGLMessage();

			var renderer, scene, camera, stats;

			var particles, uniforms;

			var PARTICLE_SIZE = 20;

			var raycaster, intersects;
			var mouse, INTERSECTED;

			init();
			animate();

			function init() {

				container = document.getElementById( 'container' );

				scene = new THREE.Scene();

				camera = new THREE.PerspectiveCamera( 45, window.innerWidth / window.innerHeight, 1, 10000 );
				camera.position.z = 250;

				//

				var geometry1 = new THREE.BoxGeometry( 200, 200, 200, 16, 16, 16 );
				var vertices = geometry1.vertices;

				var positions = new Float32Array( vertices.length * 3 );
				var colors = new Float32Array( vertices.length * 3 );
				var sizes = new Float32Array( vertices.length );

				var vertex;
				var color = new THREE.Color();

				for ( var i = 0, l = vertices.length; i < l; i ++ ) {

					vertex = vertices[ i ];
					vertex.toArray( positions, i * 3 );

					color.setHSL( 0.01 + 0.1 * ( i / l ), 1.0, 0.5 );
					color.toArray( colors, i * 3 );

					sizes[ i ] = PARTICLE_SIZE * 0.5;

				}

				var geometry = new THREE.BufferGeometry();
				geometry.addAttribute( 'position', new THREE.BufferAttribute( positions, 3 ) );
				geometry.addAttribute( 'customColor', new THREE.BufferAttribute( colors, 3 ) );
				geometry.addAttribute( 'size', new THREE.BufferAttribute( sizes, 1 ) );

				//

				var material = new THREE.ShaderMaterial( {

					uniforms: {
						color:   { value: new THREE.Color( 0xffffff ) },
						texture: { value: new THREE.TextureLoader().load( "textures/sprites/disc.png" ) }
					},
					vertexShader: document.getElementById( 'vertexshader' ).textContent,
					fragmentShader: document.getElementById( 'fragmentshader' ).textContent,

					alphaTest: 0.9

				} );

				//

				particles = new THREE.Points( geometry, material );
				scene.add( particles );

				//

				renderer = new THREE.WebGLRenderer();
				renderer.setPixelRatio( window.devicePixelRatio );
				renderer.setSize( window.innerWidth, window.innerHeight );
				container.appendChild( renderer.domElement );

				//

				raycaster = new THREE.Raycaster();
				mouse = new THREE.Vector2();

				//

				stats = new Stats();
				container.appendChild( stats.dom );

				//

				window.addEventListener( 'resize', onWindowResize, false );
				document.addEventListener( 'mousemove', onDocumentMouseMove, false );

			}

			function onDocumentMouseMove( event ) {

				event.preventDefault();

				mouse.x = ( event.clientX / window.innerWidth ) * 2 - 1;
				mouse.y = - ( event.clientY / window.innerHeight ) * 2 + 1;

			}

			function onWindowResize() {

				camera.aspect = window.innerWidth / window.innerHeight;
				camera.updateProjectionMatrix();

				renderer.setSize( window.innerWidth, window.innerHeight );

			}

			function animate() {

				requestAnimationFrame( animate );

				render();
				stats.update();

			}

			function render() {

				particles.rotation.x += 0.0005;
				particles.rotation.y += 0.001;

				var geometry = particles.geometry;
				var attributes = geometry.attributes;

				raycaster.setFromCamera( mouse, camera );

				intersects = raycaster.intersectObject( particles );

				if ( intersects.length > 0 ) {

					if ( INTERSECTED != intersects[ 0 ].index ) {

						attributes.size.array[ INTERSECTED ] = PARTICLE_SIZE;

						INTERSECTED = intersects[ 0 ].index;

						attributes.size.array[ INTERSECTED ] = PARTICLE_SIZE * 1.25;
						attributes.size.needsUpdate = true;

					}

				} else if ( INTERSECTED !== null ) {

					attributes.size.array[ INTERSECTED ] = PARTICLE_SIZE;
					attributes.size.needsUpdate = true;
					INTERSECTED = null;

				}

				renderer.render( scene, camera );

			}

		</script>

	</body>

</html>
